Exosomal long non-coding RNA TRPM2-AS promotes angiogenesis in gallbladder cancer through interacting with PABPC1 to activate NOTCH1 signaling pathway.

BACKGROUND: Abnormal angiogenesis is crucial for gallbladder cancer (GBC) tumor growth and invasion, highlighting the importance of elucidating the mechanisms underlying this process. LncRNA (long non-coding RNA) is widely involved in the malignancy of GBC. However, conclusive evidence confirming the correlation between lncRNAs and angiogenesis in GBC is lacking. METHODS: LncRNA sequencing was performed to identify the differentially expressed lncRNAs. RT-qPCR, western blot, FISH, and immunofluorescence were used to measure TRPM2-AS and NOTCH1 signaling pathway expression in vitro. Mouse xenograft and lung metastasis models were used to evaluate the biological function of TRPM2-AS during angiogenesis in vivo. EDU, transwell, and tube formation assays were used to detect the angiogenic ability of HUVECs. RIP, RAP, RNA pull-down, dual-luciferase reporter system, and mass spectrometry were used to confirm the interaction between TRPM2-AS, IGF2BP2, NUMB, and PABPC1. RESULTS: TRPM2-AS was upregulated in GBC tissues and was closely related to angiogenesis and poor prognosis in patients with GBC. The high expression level and stability of TRPM2-AS benefited from m6A modification, which is recognized by IGF2BP2. In terms of exerting pro-angiogenic effects, TRPM2-AS loaded with exosomes transported from GBC cells to HUVECs enhanced PABPC1-mediated NUMB expression inhibition, ultimately promoting the activation of the NOTCH1 signaling pathway. PABPC1 inhibited NUMB mRNA expression through interacting with AGO2 and promoted miR-31-5p and miR-146a-5p-mediated the degradation of NUMB mRNA. The NOTCH signaling pathway inhibitor DAPT inhibited GBC tumor angiogenesis, and TRPM2-AS knockdown enhanced this effect. CONCLUSIONS: TRPM2-AS is a novel and promising biomarker for GBC angiogenesis that promotes angiogenesis by facilitating the activation of the NOTCH1 signaling pathway. Targeting TRPM2-AS opens further opportunities for future GBC treatments.

Early versus delayed appendicectomy for appendiceal phlegmon or abscess.

BACKGROUND: This is an update of a Cochrane review first published in 2017. Acute appendicitis (inflammation of the appendix) can be simple or complicated. Appendiceal phlegmon and appendiceal abscess are examples of complicated appendicitis. Appendiceal phlegmon is a diffuse inflammation in the bottom right of the appendix, while appendiceal abscess is a discrete inflamed mass in the abdomen that contains pus. Appendiceal phlegmon and abscess account for 2% to 10% of acute appendicitis. People with appendiceal phlegmon or abscess usually need an appendicectomy to relieve their symptoms (e.g. abdominal pain, loss of appetite, nausea, and vomiting) and avoid complications (e.g. peritonitis (infection of abdominal lining)). Surgery for people with appendiceal phlegmon or abscess may be early (immediately after hospital admission or within a few days of admission), or delayed (several weeks later in a subsequent hospital admission). The optimal timing of appendicectomy for appendiceal phlegmon or abscess is debated. OBJECTIVES: To assess the effects of early appendicectomy compared to delayed appendicectomy on overall morbidity and mortality in people with appendiceal phlegmon or abscess. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, two other databases, and five trials registers on 11 June 2023, together with reference checking to identify additional studies. SELECTION CRITERIA: We included all individual and cluster-randomised controlled trials (RCTs), irrespective of language, publication status, or age of participants, comparing early versus delayed appendicectomy in people with appendiceal phlegmon or abscess. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. MAIN RESULTS: We included eight RCTs that randomised 828 participants to early or delayed appendicectomy for appendiceal phlegmon (7 trials) or appendiceal abscess (1 trial). The studies were conducted in the USA, India, Nepal, and Pakistan. All RCTs were at high risk of bias because of lack of blinding and lack of published protocols. They were also unclear about methods of randomisation and length of follow-up. 1. Early versus delayed open or laparoscopic appendicectomy for appendiceal phlegmon We included seven trials involving 788 paediatric and adult participants with appendiceal phlegmon: 394 of the participants were randomised to the early appendicectomy group (open or laparoscopic appendicectomy as soon as the appendiceal mass resolved within the same admission), and 394 were randomised to the delayed appendicectomy group (initial conservative treatment followed by delayed open or laparoscopic appendicectomy several weeks later). There was no mortality in either group. The evidence is very uncertain about the effect of early appendicectomy on overall morbidity (risk ratio (RR) 0.74, 95% confidence interval (CI) 0.19 to 2.86; 3 trials, 146 participants; very low-certainty evidence), the proportion of participants who developed wound infections (RR 0.99, 95% CI 0.48 to 2.02; 7 trials, 788 participants), and the proportion of participants who developed faecal fistulas (RR 1.75, 95% CI 0.36 to 8.49; 5 trials, 388 participants). Early appendicectomy may reduce the abdominal abscess rate (RR 0.26, 95% CI 0.08 to 0.80; 4 trials, 626 participants; very low-certainty evidence), reduce the total length of hospital stay by about two days (mean difference (MD) -2.02 days, 95% CI -3.13 to -0.91; 5 trials, 680 participants), and increase the time away from normal activities by about five days (MD 5.00 days; 95% CI 1.52 to 8.48; 1 trial, 40 participants), but the evidence is very uncertain. 2. Early versus delayed laparoscopic appendicectomy for appendiceal abscess We included one trial involving 40 paediatric participants with appendiceal abscess: 20 were randomised to the early appendicectomy group (emergent laparoscopic appendicectomy), and 20 were randomised to the delayed appendicectomy group (initial conservative treatment followed by delayed laparoscopic appendicectomy 10 weeks later). There was no mortality in either group. The trial did not report on overall morbidity, various complications, or time away from normal activities. The evidence is very uncertain about the effect of early appendicectomy on the total length of hospital stay (MD -0.20 days, 95% CI -3.54 to 3.14; very low-certainty evidence). AUTHORS' CONCLUSIONS: For the comparison of early versus delayed open or laparoscopic appendicectomy for paediatric and adult participants with appendiceal phlegmon, very low-certainty evidence suggests that early appendicectomy may reduce the abdominal abscess rate. The evidence is very uncertain whether early appendicectomy prevents overall morbidity or other complications. Early appendicectomy may reduce the total length of hospital stay and increase the time away from normal activities, but the evidence is very uncertain. For the comparison of early versus delayed laparoscopic appendicectomy for paediatric participants with appendiceal abscess, data are sparse, and we cannot rule out significant benefits or harms of early versus delayed appendicectomy. Further trials on this topic are urgently needed and should specify a set of criteria for use of antibiotics, percutaneous drainage of the appendiceal abscess prior to surgery, and resolution of the appendiceal phlegmon or abscess. Future trials should include outcomes such as time away from normal activities and length of hospital stay.

Laparoscopic versus open oncological extended re-resection for incidental gallbladder adenocarcinoma: we can do more than T1/2.

BACKGROUND: The laparoscopic and open approaches have comparable safety and oncological efficacy to treat early (T1b or T2) stage incidental gallbladder cancer (IGBC). However, their effects on T3 stage or above tumors unclear. METHODS: Data of IGBC patients who underwent radical re-resection were retrospectively analyzed. Demographic characteristics, surgical variables, and tumor characteristics were evaluated for association with survival. RESULTS: We analyzed retrospectively 201 patients (72 men, 129 women; median age 63 years; range, 36-85 years). 84 underwent laparoscopic re-resection and 117 underwent open surgery. The 5-year OS post-resection was 74.7%, with a median survival of 74.52 months. The median OS (73.92 months vs. 77.04 months, P = 0.67), and disease-free survival (72.60 months vs. 71.09 months, P = 0.18) were comparable between the laparoscopic re-resection and open surgery groups. The survival of patients with T1/T2 (median: 85.50 months vs. 80.14 months; P = 0.67) and T3 (median: 68.56 months vs. 58.85 months; P = 0.36) disease were comparable between the open re-resection and laparoscopic re-resection groups even after PS matching. Open surgery group lost significantly more blood, while laparoscopic surgery took longer. The postsurgical stay in the laparoscopic re-resection group was significantly shorter. Combined extrahepatic bile duct resection, gallbladder perforation, pT, pStage, histological grade, microscopic liver invasion, status of the resected margin, and adjuvant therapy comprised significant independent prognostic indicators for IGBC. CONCLUSIONS: Laparoscopic and open surgery can achieve similar short and long-term outcomes for T3 IGBC; however, careful surgical manipulation is necessary to avoid secondary injuries.

Fibrin sealants for the prevention of postoperative pancreatic fistula following pancreatic surgery.

BACKGROUND: Postoperative pancreatic fistula (POPF) is one of the most frequent and potentially life-threatening complications following pancreatic surgery. Fibrin sealants have been used in some centres to reduce POPF rate. However, the use of fibrin sealant during pancreatic surgery is controversial. This is an update of a Cochrane Review last published in 2020. OBJECTIVES: To evaluate the benefits and harms of fibrin sealant use for the prevention of POPF (grade B or C) in people undergoing pancreatic surgery compared to no fibrin sealant use. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, two other databases, and five trials registers on 09 March 2023, together with reference checking, citation searching, and contacting study authors to identify additional studies. SELECTION CRITERIA: We included all randomised controlled trials (RCTs) that compared fibrin sealant (fibrin glue or fibrin sealant patch) versus control (no fibrin sealant or placebo) in people undergoing pancreatic surgery. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. MAIN RESULTS: We included 14 RCTs, randomising 1989 participants, comparing fibrin sealant use versus no fibrin sealant use for different locations: stump closure reinforcement (eight trials), pancreatic anastomosis reinforcement (five trials), or main pancreatic duct occlusion (two trials). Six RCTs were carried out in single centres; two in dual centres; and six in multiple centres. One RCT was conducted in Australia; one in Austria; two in France; three in Italy; one in Japan; two in the Netherlands; two in South Korea; and two in the USA. The mean age of the participants ranged from 50.0 years to 66.5 years. All RCTs were at high risk of bias. Application of fibrin sealants to pancreatic stump closure reinforcement after distal pancreatectomy We included eight RCTs involving 1119 participants: 559 were randomised to the fibrin sealant group and 560 to the control group after distal pancreatectomy. Fibrin sealant use may result in little to no difference in the rate of POPF (risk ratio (RR) 0.94, 95% confidence interval (CI) 0.73 to 1.21; 5 studies, 1002 participants; low-certainty evidence) and overall postoperative morbidity (RR 1.20, 95% CI 0.98 to 1.48; 4 studies, 893 participants; low-certainty evidence). After fibrin sealant use, approximately 199 people (155 to 256 people) out of 1000 developed POPF compared with 212 people out of 1000 when no fibrin sealant was used. The evidence is very uncertain about the effect of fibrin sealant use on postoperative mortality (Peto odds ratio (OR) 0.39, 95% CI 0.12 to 1.29; 7 studies, 1051 participants; very low-certainty evidence) and total length of hospital stay (mean difference (MD) 0.99 days, 95% CI -1.83 to 3.82; 2 studies, 371 participants; very low-certainty evidence). Fibrin sealant use may reduce the reoperation rate slightly (RR 0.40, 95% CI 0.18 to 0.90; 3 studies, 623 participants; low-certainty evidence). Serious adverse events were reported in five studies (732 participants), and there were no serious adverse events related to fibrin sealant use (low-certainty evidence). The studies did not report quality of life or cost-effectiveness. Application of fibrin sealants to pancreatic anastomosis reinforcement after pancreaticoduodenectomy We included five RCTs involving 519 participants: 248 were randomised to the fibrin sealant group and 271 to the control group after pancreaticoduodenectomy. The evidence is very uncertain about the effect of fibrin sealant use on the rate of POPF (RR 1.34, 95% CI 0.72 to 2.48; 3 studies, 323 participants; very low-certainty evidence), postoperative mortality (Peto OR 0.24, 95% CI 0.05 to 1.06; 5 studies, 517 participants; very low-certainty evidence), reoperation rate (RR 0.74, 95% CI 0.33 to 1.66; 3 studies, 323 participants; very low-certainty evidence), and total hospital cost (MD -1489.00 US dollars, 95% CI -3256.08 to 278.08; 1 study, 124 participants; very low-certainty evidence). After fibrin sealant use, approximately 130 people (70 to 240 people) out of 1000 developed POPF compared with 97 people out of 1000 when no fibrin sealant was used. Fibrin sealant use may result in little to no difference both in overall postoperative morbidity (RR 1.02, 95% CI 0.87 to 1.19; 4 studies, 447 participants; low-certainty evidence) and in total length of hospital stay (MD -0.33 days, 95% CI -2.30 to 1.63; 4 studies, 447 participants; low-certainty evidence). Serious adverse events were reported in two studies (194 participants), and there were no serious adverse events related to fibrin sealant use (very low-certainty evidence). The studies did not report quality of life. Application of fibrin sealants to pancreatic duct occlusion after pancreaticoduodenectomy We included two RCTs involving 351 participants: 188 were randomised to the fibrin sealant group and 163 to the control group after pancreaticoduodenectomy. The evidence is very uncertain about the effect of fibrin sealant use on postoperative mortality (Peto OR 1.41, 95% CI 0.63 to 3.13; 2 studies, 351 participants; very low-certainty evidence), overall postoperative morbidity (RR 1.16, 95% CI 0.67 to 2.02; 2 studies, 351 participants; very low-certainty evidence), and reoperation rate (RR 0.85, 95% CI 0.52 to 1.41; 2 studies, 351 participants; very low-certainty evidence). Fibrin sealant use may result in little to no difference in the total length of hospital stay (median 16 to 17 days versus 17 days; 2 studies, 351 participants; low-certainty evidence). Serious adverse events were reported in one study (169 participants; low-certainty evidence): more participants developed diabetes mellitus when fibrin sealants were applied to pancreatic duct occlusion, both at three months' follow-up (33.7% fibrin sealant group versus 10.8% control group; 29 participants versus 9 participants) and 12 months' follow-up (33.7% fibrin sealant group versus 14.5% control group; 29 participants versus 12 participants). The studies did not report POPF, quality of life, or cost-effectiveness. AUTHORS' CONCLUSIONS: Based on the current available evidence, fibrin sealant use may result in little to no difference in the rate of POPF in people undergoing distal pancreatectomy. The evidence is very uncertain about the effect of fibrin sealant use on the rate of POPF in people undergoing pancreaticoduodenectomy. The effect of fibrin sealant use on postoperative mortality is uncertain in people undergoing either distal pancreatectomy or pancreaticoduodenectomy.

Timing of surgery in patients with synchronous colorectal cancer liver metastases undergoing neoadjuvant chemotherapy: a propensity score analysis.

BACKGROUND: The optimal timing of surgery after neoadjuvant chemotherapy (NAC) in patients with synchronous colorectal cancer liver metastases (SLM) remains controversial. We plan to analyze whether the choice of different surgical timings will have different effects on the perioperative and oncologic outcomes of patients. METHOD: We retrospectively collected all patients who met the inclusion and exclusion criteria from 2010 to 2020 in West China Hospital. Patients were grouped according to time interval (TI) after NAC to surgery. The perioperative and oncologic outcomes of the two groups were compared after propensity score matching. Univariate and multivariate analyzes were used to screen factors associated with prognosis. RESULT: Among 255 enrolled patients, 188 were matched with comparable baseline (94 each group). Patients in the 6≦TI≦8 group had longer operation time, less intraoperative blood loss, and less postoperative complications than those in the 4≦TI < 6 group. However, the overall survival (OS) (p = 0.012) and disease-free survival (DFS) (p = 0.013) of the patients in the 4≦TI < 6 group were better than those in the 6≦TI≦8 group. Subgroup analysis found that the above conclusions still apply in age ≥ 60, non-anemic patients, and patients who underwent R0 resection. OS was inversely correlated with TI in patients without preoperative jaundice. DFS was negatively correlated with TI in patients with preoperative jaundice. Multivariate analysis showed that the prolongation of TI after NAC to surgery was an independent prognostic risk factor for OS and DFS. CONCLUSIONS: Patients with SLM may be a better choice for surgery within 4-6 weeks after receiving NAC. Although patients with SLM undergoing surgery 4-6 weeks after NAC has a higher rate of postoperative complications, radical surgery is still recommended for a better survival benefit.

Protein-Recognition-Initiated Exponential Amplification Reaction (PRIEAR) and Its Application in Clinical Diagnosis.

Isothermal exponential amplification technology has rarely been fabricated as a universal sensing platform for the detection of proteins. To broaden their application, we have developed a strategy, named protein-recognition-initiated exponential amplification reaction (PRIEAR) using protein recognition to induce DNA assembly, which converts protein recognition events into ssDNA amplicons and combines two-stage amplification to achieve exponential amplification. Taking advantage of this principle, diverse biomarkers can be quantified at sub-picomolar concentrations in a homogenous manner, making PRIEAR suitable for clinical settings. Therefore, this strategy can expand the powerful isothermal exponential amplification technology to protein targets and thus provide a new toolbox in clinical and biomedical applications.

Gases for establishing pneumoperitoneum during laparoscopic abdominal surgery.

BACKGROUND: This is the second update of a Cochrane Review first published in 2013 and last updated in 2017. Laparoscopic surgery is now widely performed to treat various abdominal diseases. Currently, carbon dioxide is the most frequently used gas for insufflation of the abdominal cavity (pneumoperitoneum). Although carbon dioxide meets most of the requirements for pneumoperitoneum, the absorption of carbon dioxide may be associated with adverse events. Therefore, other gases have been introduced as alternatives to carbon dioxide for establishing pneumoperitoneum. OBJECTIVES: To assess the safety, benefits, and harms of different gases (e.g. carbon dioxide, helium, argon, nitrogen, nitrous oxide, and room air) used for establishing pneumoperitoneum in participants undergoing laparoscopic abdominal or gynaecological pelvic surgery. SEARCH METHODS: We searched CENTRAL, Ovid MEDLINE, Ovid Embase, four other databases, and three trials registers on 15 October 2021 together with reference checking, citation searching, and contact with study authors to identify additional studies. SELECTION CRITERIA: We included randomised controlled trials (RCTs) comparing different gases for establishing pneumoperitoneum in participants (irrespective of age, sex, or race) undergoing laparoscopic abdominal or gynaecological pelvic surgery under general anaesthesia. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. MAIN RESULTS: We included 10 RCTs, randomising 583 participants, comparing different gases for establishing pneumoperitoneum: nitrous oxide (four trials), helium (five trials), or room air (one trial) was compared to carbon dioxide. All the RCTs were single-centre studies. Four RCTs were conducted in the USA; two in Australia; one in China; one in Finland; one in Iran; and one in the Netherlands. The mean age of the participants ranged from 27.6 years to 49.0 years. Four trials randomised participants to nitrous oxide pneumoperitoneum (132 participants) or carbon dioxide pneumoperitoneum (128 participants). None of the trials was at low risk of bias. The evidence is very uncertain about the effects of nitrous oxide pneumoperitoneum compared to carbon dioxide pneumoperitoneum on cardiopulmonary complications (Peto odds ratio (OR) 2.62, 95% CI 0.78 to 8.85; 3 studies, 204 participants; very low-certainty evidence), or surgical morbidity (Peto OR 1.01, 95% CI 0.14 to 7.31; 3 studies, 207 participants; very low-certainty evidence). There were no serious adverse events related to either nitrous oxide or carbon dioxide pneumoperitoneum (4 studies, 260 participants; very low-certainty evidence). Four trials randomised participants to helium pneumoperitoneum (69 participants) or carbon dioxide pneumoperitoneum (75 participants) and one trial involving 33 participants did not state the number of participants in each group. None of the trials was at low risk of bias. The evidence is very uncertain about the effects of helium pneumoperitoneum compared to carbon dioxide pneumoperitoneum on cardiopulmonary complications (Peto OR 1.66, 95% CI 0.28 to 9.72; 3 studies, 128 participants; very low-certainty evidence), or surgical morbidity (5 studies, 177 participants; very low-certainty evidence). There were three serious adverse events (subcutaneous emphysema) related to helium pneumoperitoneum (3 studies, 128 participants; very low-certainty evidence). One trial randomised participants to room air pneumoperitoneum (70 participants) or carbon dioxide pneumoperitoneum (76 participants). The trial was at high risk of bias. There were no cardiopulmonary complications, serious adverse events, or deaths observed related to either room air or carbon dioxide pneumoperitoneum.    AUTHORS' CONCLUSIONS: The evidence is very uncertain about the effects of nitrous oxide, helium, and room air pneumoperitoneum compared to carbon dioxide pneumoperitoneum on any of the primary outcomes, including cardiopulmonary complications, surgical morbidity, and serious adverse events. The safety of nitrous oxide, helium, and room air pneumoperitoneum has yet to be established, especially in people with high anaesthetic risk.

Laparoscopic surgery for oncologic extended resection of T1b and T2 incidental gallbladder carcinoma at a high-volume center: a single-center experience in China.

BACKGROUND: Surgical treatment is still the most effective treatment for gallbladder cancer. For the patients with stage T1b and above, the current guidelines recommend the extended radical operation, and oncologic extended resection can benefit the survival of the patients. The laparoscopic approach is still in the early phase, and its safety and oncological outcomes are not well known. OBJECTIVE: To evaluate the technical feasibility and oncological outcomes of laparoscopic surgery for oncologic extended resection of early-stage incidental gallbladder carcinoma. RESULTS: This study included 18 male and 32 female patients. Twenty patients underwent laparoscopic oncologic extended resection and 30 patients underwent open oncologic extended resection. All of the patients had R0 resection. A laparoscopic approach was associated with less intraoperative blood loss (242 ± 108.5 vs 401 ± 130.3; p < 0.01) and shorter duration of postoperative hospital stay (6.2 ± 2.4 vs 8.6 ± 2.3; p < 0.01). There was no statistically significant difference between two groups for lymph nodes yield (5.4 ± 3.5 vs 5.8 ± 2.1; p > 0.05), incidence of lymphatic metastasis (15% vs 16.67%; p > 0.05), residual disease (20% vs 23.3%; p > 0.05), and postoperative morbidity (15% vs 20%; p > 0.05). During follow-up time of median 20.95 (12-29.5) months, no significant difference was found between the two groups for early tumor recurrence (10% vs 13.33%; p > 0.05) and disease-free survival (p > 0.05). CONCLUSION: Laparoscopic surgery may offer similar intraoperative, perioperative, and short-term oncological outcomes as an open oncologic extended resection for incidental gallbladder carcinoma.

Abdominal drainage to prevent intra-peritoneal abscess after appendectomy for complicated appendicitis.

BACKGROUND: This is the second update of a Cochrane Review first published in 2015 and last updated in 2018. Appendectomy, the surgical removal of the appendix, is performed primarily for acute appendicitis. Patients who undergo appendectomy for complicated appendicitis, defined as gangrenous or perforated appendicitis, are more likely to suffer postoperative complications. The routine use of abdominal drainage to reduce postoperative complications after appendectomy for complicated appendicitis is controversial. OBJECTIVES: To assess the safety and efficacy of abdominal drainage to prevent intraperitoneal abscess after appendectomy (irrespective of open or laparoscopic) for complicated appendicitis; to compare the effects of different types of surgical drains; and to evaluate the optimal time for drain removal. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), Ovid MEDLINE, Ovid Embase, Web of Science, the World Health Organization International Trials Registry Platform, ClinicalTrials.gov, Chinese Biomedical Literature Database, and three trials registers on 24 February 2020, together with reference checking, citation searching, and contact with study authors to identify additional studies. SELECTION CRITERIA: We included all randomised controlled trials (RCTs) that compared abdominal drainage versus no drainage in people undergoing emergency open or laparoscopic appendectomy for complicated appendicitis. We also included RCTs that compared different types of drains and different schedules for drain removal in people undergoing appendectomy for complicated appendicitis. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. Two review authors independently identified the trials for inclusion, collected the data, and assessed the risk of bias. We used the GRADE approach to assess evidence certainty. We included intraperitoneal abscess as the primary outcome. Secondary outcomes were wound infection, morbidity, mortality, hospital stay, hospital costs, pain, and quality of life. MAIN RESULTS: Use of drain versus no drain We included six RCTs (521 participants) comparing abdominal drainage and no drainage in participants undergoing emergency open appendectomy for complicated appendicitis. The studies were conducted in North America, Asia, and Africa. The majority of participants had perforated appendicitis with local or general peritonitis. All participants received antibiotic regimens after open appendectomy. None of the trials was assessed as at low risk of bias. The evidence is very uncertain regarding the effects of abdominal drainage versus no drainage on intraperitoneal abscess at 30 days (risk ratio (RR) 1.23, 95% confidence interval (CI) 0.47 to 3.21; 5 RCTs; 453 participants; very low-certainty evidence) or wound infection at 30 days (RR 2.01, 95% CI 0.88 to 4.56; 5 RCTs; 478 participants; very low-certainty evidence). There were seven deaths in the drainage group (N = 183) compared to one in the no-drainage group (N = 180), equating to an increase in the risk of 30-day mortality from 0.6% to 2.7% (Peto odds ratio 4.88, 95% CI 1.18 to 20.09; 4 RCTs; 363 participants; low-certainty evidence). Abdominal drainage may increase 30-day overall complication rate (morbidity; RR 6.67, 95% CI 2.13 to 20.87; 1 RCT; 90 participants; low-certainty evidence) and hospital stay by 2.17 days (95% CI 1.76 to 2.58; 3 RCTs; 298 participants; low-certainty evidence) compared to no drainage. The outcomes hospital costs, pain, and quality of life were not reported in any of the included studies. There were no RCTs comparing the use of drain versus no drain in participants undergoing emergency laparoscopic appendectomy for complicated appendicitis. Open drain versus closed drain There were no RCTs comparing open drain versus closed drain for complicated appendicitis. Early versus late drain removal There were no RCTs comparing early versus late drain removal for complicated appendicitis. AUTHORS' CONCLUSIONS: The certainty of the currently available evidence is low to very low. The effect of abdominal drainage on the prevention of intraperitoneal abscess or wound infection after open appendectomy is uncertain for patients with complicated appendicitis. The increased rates for overall complication rate and hospital stay for the drainage group compared to the no-drainage group are based on low-certainty evidence. Consequently, there is no evidence for any clinical improvement with the use of abdominal drainage in patients undergoing open appendectomy for complicated appendicitis. The increased risk of mortality with drainage comes from eight deaths observed in just under 400 recruited participants. Larger studies are needed to more reliably determine the effects of drainage on morbidity and mortality outcomes.

Prophylactic abdominal drainage for pancreatic surgery.

BACKGROUND: The use of surgical drains is a very common practice after pancreatic surgery. The role of prophylactic abdominal drainage to reduce postoperative complications after pancreatic surgery is controversial. This is the third update of a previously published Cochrane Review to address the uncertain benifits of prophylactic abdominal drainage in pancreatic surgery. OBJECTIVES: To assess the benefits and harms of routine abdominal drainage after pancreatic surgery, compare the effects of different types of surgical drains, and evaluate the optimal time for drain removal. SEARCH METHODS: In this updated review, we re-searched CENTRAL, MEDLINE, Embase, Science Citation Index Expanded, and the Chinese Biomedical Literature Database (CBM) on 08 February 2021. SELECTION CRITERIA: We included all randomised controlled trials (RCTs) that compared abdominal drainage versus no drainage in people undergoing pancreatic surgery. We also included RCTs that compared different types of drains and different schedules for drain removal in people undergoing pancreatic surgery. DATA COLLECTION AND ANALYSIS: Two review authors independently identified the studies for inclusion, collected the data, and assessed the risk of bias. We conducted the meta-analyses using Review Manager 5. We calculated the risk ratio (RR) for dichotomous outcomes and the mean difference (MD) or standardized mean difference (SMD) for continuous outcomes with 95% confidence intervals (CI). For all analyses, we used the random-effects model. We used GRADE to assess the certainty of the evidence for important outcomes. MAIN RESULTS: We identified a total of nine RCTs with 1892 participants. Drain use versus no drain use We included four RCTs with 1110 participants, randomised to the drainage group (N = 560) and the no drainage group (N = 550) after pancreatic surgery. Low-certainty evidence suggests that drain use may reduce 90-day mortality (RR 0.23, 95% CI 0.06 to 0.90; two studies, 478 participants). Compared with no drain use, low-certainty evidence suggests that drain use may result in little to no difference in 30-day mortality (RR 0.78, 95% CI 0.31 to 1.99; four studies, 1055 participants), wound infection rate (RR 0.98, 95% CI 0.68 to 1.41; four studies, 1055 participants), length of hospital stay (MD -0.14 days, 95% CI -0.79 to 0.51; three studies, 876 participants), the need for additional open procedures for postoperative complications (RR 1.33, 95% CI 0.79 to 2.23; four studies, 1055 participants), and quality of life (105 points versus 104 points; measured with the pancreas-specific quality of life questionnaire (scale 0 to 144, higher values indicating a better quality of life); one study, 399 participants). There was one drain-related complication in the drainage group (0.2%). Moderate-certainty evidence suggests that drain use probably resulted in little to no difference in morbidity (RR 1.03, 95% CI 0.94 to 1.13; four studies, 1055 participants). The evidence was very uncertain about the effect of drain use on intra-abdominal infection rate (RR 0.97, 95% CI 0.52 to 1.80; four studies, 1055 participants; very low-certainty evidence), and the need for additional radiological interventions for postoperative complications (RR 0.87, 95% CI 0.40 to 1.87; three studies, 660 participants; very low-certainty evidence). Active versus passive drain We included two RCTs involving 383 participants, randomised to the active drain group (N = 194) and the passive drain group (N = 189) after pancreatic surgery. Compared with a passive drain, the evidence was very uncertain about the effect of an active drain on 30-day mortality (RR 1.23, 95% CI 0.30 to 5.06; two studies, 382 participants; very low-certainty evidence), intra-abdominal infection rate (RR 0.87, 95% CI 0.21 to 3.66; two studies, 321 participants; very low-certainty evidence), wound infection rate (RR 0.92, 95% CI 0.44 to 1.90; two studies, 321 participants; very low-certainty evidence), morbidity (RR 0.97, 95% CI 0.53 to 1.77; two studies, 382 participants; very low-certainty evidence), length of hospital stay (MD -0.79 days, 95% CI -2.63 to 1.04; two studies, 321 participants; very low-certainty evidence), and the need for additional open procedures for postoperative complications (RR 0.44, 95% CI 0.11 to 1.83; two studies, 321 participants; very low-certainty evidence). There was no drain-related complication in either group. Early versus late drain removal We included three RCTs involving 399 participants with a low risk of postoperative pancreatic fistula, randomised to the early drain removal group (N = 200) and the late drain removal group (N = 199) after pancreatic surgery. Compared to late drain removal, the evidence was very uncertain about the effect of early drain removal on 30-day mortality (RR 0.99, 95% CI 0.06 to 15.45; three studies, 399 participants; very low-certainty evidence), wound infection rate (RR 1.32, 95% CI 0.45 to 3.85; two studies, 285 participants; very low-certainty evidence), hospital costs (SMD -0.22, 95% CI -0.59 to 0.14; two studies, 258 participants; very low-certainty evidence), the need for additional open procedures for postoperative complications (RR 0.77, 95% CI 0.28 to 2.10; three studies, 399 participants; very low-certainty evidence), and the need for additional radiological procedures for postoperative complications (RR 1.00, 95% CI 0.21 to 4.79; one study, 144 participants; very low-certainty evidence). We found that early drain removal may reduce intra-abdominal infection rate (RR 0.44, 95% CI 0.22 to 0.89; two studies, 285 participants; very low-certainty evidence), morbidity (RR 0.49, 95% CI 0.30 to 0.81; two studies, 258 participants; very low-certainty evidence), and length of hospital stay (MD -2.20 days, 95% CI -3.52 to -0.87; three studies, 399 participants; very low-certainty evidence), but the evidence was very uncertain. None of the studies reported on drain-related complications. AUTHORS' CONCLUSIONS: Compared with no drain use, it is unclear whether routine drain use has any effect on mortality at 30 days or postoperative complications after pancreatic surgery. Compared with no drain use, low-certainty evidence suggests that routine drain use may reduce mortality at 90 days. Compared with a passive drain, the evidence is very uncertain about the effect of an active drain on mortality at 30 days or postoperative complications. Compared with late drain removal, early drain removal may reduce intra-abdominal infection rate, morbidity, and length of hospital stay for people with low risk of postoperative pancreatic fistula, but the evidence is very uncertain.

The preoperative elevated plasma fibrinogen level is associated with the prognosis of hilar cholangiocarcinoma.

PURPOSE: Elevated fibrinogen (Fbg) levels contribute to tumor progression and metastasis. However, little is known regarding the association of the clinicopathological characteristics and the prognosis of hilar cholangiocarcinoma (HC) with plasma fibrinogen. METHODS: Data on the plasma Fbg levels, clinicopathological characteristics, and overall survival were retrospectively collected. Plasma fibrinogen concentrations over 4.0 g/L were classified as hyperfibrinogen, elevated fibrinogen, or abnormal fibrinogen levels. We then analyzed the relationships among plasma fibrinogen level, clinicopathological features, and patient prognosis. RESULTS: A total of 171 HC patients were included. An elevated plasma fibrinogen level was associated with lymph-node metastasis (P < 0.001), the AJCC stage (P < 0.001), the surgical margin (P = 0.005), and vascular invasion (P = 0.027). Univariate analyses revealed that preoperative plasma fibrinogen (P < 0.001), operative blood loss (P = 0.044), vascular invasion (P < 0.001), CA19-9 (P = 0.003), surgical margin (P < 0.001), T stage (P < 0.001), histologic differentiation (P = 0.007), and lymph-node metastasis (P < 0.001) were associated with OS. The survival time of patients with high Fbg levels was shorter than that of patients with normal fibrinogen levels (P < 0.001). Furthermore, a multivariate analysis showed that fibrinogen was negatively and independently associated with the HC prognosis (P = 0.029). CONCLUSIONS: An elevated plasma Fbg level was associated with lymph-node metastasis, vascular invasion, the surgical margin, and the tumor stage, and the Fbg level might therefore be an independent factor associated with poor outcomes in HC patients.

Spatially Constrained DNA Nanomachines To Accelerate Kinetics in Response to External Input: Design and Bioanalysis.

Cells take advantage of the spatial organization to accelerate the reaction kinetics of diverse components within a crowded intracellular environment. Inspired by this, we hereby designed a principle of spatial constraint to overcome limitations of response kinetics in DNAzyme-powered DNA nanomachines. First, we proposed the type-1 of spatially constrained DNA nanomachines (scDN-1) by co-localizing the aptamer probe and power unit (DNAzyme), allowing the DNA nanomachines to accomplish faster cyclic cleavage of DNAzyme as intramolecular reactions. To expand the scDN into the clinical practice, Type 2 spatially constrained DNA nanomachines (scDN-2) with constrained antibody probes were then constructed through Holliday junction assembly, which increased the effective local concentration to obtain the improved kinetics. With an accelerated response kinetics, this design principle allows DNA nanomachines to accomplish the response to tumor markers in real patients' samples within 30 min, significantly broadening the bioanalytical applications of DNA nanomachines to clinical practice.

A Novel Nomogram Predicting Distant Metastasis in T1 and T2 Gallbladder Cancer: A SEER-based Study.

Background: Gallbladder cancer (GBC) is the most common malignancy of the biliary system. Early T stage GBC patients with distant metastasis are proven to have a worse prognosis. In this study, our aim was to construct and validate a novel nomogram for predicting distant metastasis in T1 and T2 GBC. Methods: Between 2004 and 2014, patients with T1 and T2 GBC were identified in the Surveillance, Epidemiology, and End Results (SEER) database. All of the eligible patients were randomly divided into training and validation cohorts. Univariate and multivariate analyses were used to assess significant predictive factors associated with distant metastasis. A nomogram was developed and validated by a calibration curve and receptor operating characteristic curve (ROC) analysis. Results: According to the inclusion and exclusion criteria, 3013 patients with historically confirmed AJCC stage T1 and T2 GBC were enrolled. Younger age, high pathological grade, nonadenocarcinoma, T1, N1 and larger tumor size correlated positively with the risk of distant metastasis. A novel nomogram was established to predict distant metastasis in early T stage GBC patients. Internal validation with a calibration plot in the training cohort showed that this nomogram was well calibrated. Through ROC curve analysis, the areas under the ROC curves in the training and validation cohorts were 0.723 and 0.679, respectively. Conclusions: Although some limitations exist in this predictive model, the nomogram revealed the relationship between the clinicopathological characteristics of T1 and T2 GBC patients and the risk of distant metastasis. The novel nomogram will assist in patient counseling and guide treatment decision making for T1 and T2 GBC patients.

Fibrin sealants for the prevention of postoperative pancreatic fistula following pancreatic surgery.

BACKGROUND: Postoperative pancreatic fistula is one of the most frequent and potentially life-threatening complications following pancreatic resections. Fibrin sealants have been used in some centers to reduce postoperative pancreatic fistula. However, the use of fibrin sealants during pancreatic surgery is controversial. This is an update of a Cochrane Review last published in 2018. OBJECTIVES: To assess the safety, effectiveness, and potential adverse effects of fibrin sealants for the prevention of postoperative pancreatic fistula following pancreatic surgery. SEARCH METHODS: We searched trial registers and the following biomedical databases: the Cochrane Library (2019, Issue 2), MEDLINE (1946 to 13 March2019), Embase (1980 to 11 March 2019), Science Citation Index Expanded (1900 to 13 March 2019), and Chinese Biomedical Literature Database (CBM) (1978 to 13 March 2019). SELECTION CRITERIA: We included all randomised controlled trials that compared fibrin sealant (fibrin glue or fibrin sealant patch) versus control (no fibrin sealant or placebo) in people undergoing pancreatic surgery. DATA COLLECTION AND ANALYSIS: Two review authors independently identified the trials for inclusion, collected the data, and assessed the risk of bias. We performed the meta-analyses using Review Manager 5. We calculated the risk ratio (RR) for dichotomous outcomes (or a Peto odds ratio (OR) for very rare outcomes), and the mean difference (MD) for continuous outcomes, with 95% confidence intervals (CIs). MAIN RESULTS: We included 12 studies involving 1604 participants in the review. Application of fibrin sealants to pancreatic stump closure reinforcement after distal pancreatectomy We included seven studies involving 860 participants: 428 were randomised to the fibrin sealant group and 432 to the control group after distal pancreatectomy. Fibrin sealants may lead to little or no difference in postoperative pancreatic fistula (fibrin sealant 19.3%; control 20.1%; RR 0.96, 95% CI 0.68 to 1.35; 755 participants; four studies; low-quality evidence). Fibrin sealants may also lead to little or no difference in postoperative mortality (0.3% versus 0.5%; Peto OR 0.52, 95% CI 0.05 to 5.03; 804 participants; six studies; low-quality evidence), or overall postoperative morbidity (28.5% versus 23.2%; RR 1.23, 95% CI 0.97 to 1.58; 646 participants; three studies; low-quality evidence). We are uncertain whether fibrin sealants reduce reoperation rate (2.0% versus 3.8%; RR 0.51, 95% CI 0.15 to 1.71; 376 participants; two studies; very low-quality evidence) or length of hospital stay (MD 0.99 days, 95% CI -1.83 to 3.82; 371 participants; two studies; very low-quality evidence). The studies did not report serious adverse events, quality of life, or cost effectiveness. Application of fibrin sealants to pancreatic anastomosis reinforcement after pancreaticoduodenectomy We included four studies involving 393 participants: 186 were randomised to the fibrin sealant group and 207 to the control group after pancreaticoduodenectomy. We are uncertain whether fibrin sealants reduce postoperative pancreatic fistula (16.7% versus 11.7%; RR 1.14, 95% CI 0.28 to 4.69; 199 participants; two studies; very low-quality evidence). We are uncertain whether fibrin sealants reduce postoperative mortality (0.5% versus 2.4%; Peto OR 0.26, 95% CI 0.05 to 1.32; 393 participants; four studies; low-quality evidence) or length of hospital stay (MD 0.01 days, 95% CI -3.91 to 3.94; 323 participants; three studies; very low-quality evidence). There is probably little or no difference in overall postoperative morbidity (52.6% versus 50.3%; RR 1.04, 95% CI 0.87 to 1.24; 323 participants; three studies; moderate-quality evidence) between the groups. We are uncertain whether fibrin sealants reduce reoperation rate (5.2% versus 7.7%; RR 0.74, 95% CI 0.33 to 1.66; 323 participants; three studies, very low-quality evidence). The studies did not report serious adverse events, quality of life, or cost effectiveness. Application of fibrin sealants to pancreatic duct occlusion after pancreaticoduodenectomy We included two studies involving 351 participants: 188 were randomised to the fibrin sealant group and 163 to the control group after pancreaticoduodenectomy. Fibrin sealants may lead to little or no difference in postoperative mortality (8.4% versus 6.1%; Peto OR 1.41, 95% CI 0.63 to 3.13; 351 participants; two studies; low-quality evidence) or length of hospital stay (median 16 to 17 days versus 17 days; 351 participants; two studies; low-quality evidence). We are uncertain whether fibrin sealants reduce overall postoperative morbidity (32.0% versus 27.6%; RR 1.16, 95% CI 0.67 to 2.02; 351 participants; two studies; very low-quality evidence), or reoperation rate (13.6% versus 16.0%; RR 0.85, 95% CI 0.52 to 1.41; 351 participants; two studies; very low-quality evidence). Serious adverse events were reported in one study (169 participants; low-quality evidence): more participants developed diabetes mellitus when fibrin sealants were applied to pancreatic duct occlusion, both at three months' follow-up (33.7% fibrin sealant group versus 10.8% control group; 29 participants versus 9 participants) and 12 months' follow-up (33.7% fibrin sealant group versus 14.5% control group; 29 participants versus 12 participants). The studies did not report postoperative pancreatic fistula, quality of life, or cost effectiveness. AUTHORS' CONCLUSIONS: Based on the current available evidence, fibrin sealants may have little or no effect on postoperative pancreatic fistula in people undergoing distal pancreatectomy. The effects of fibrin sealants on the prevention of postoperative pancreatic fistula are uncertain in people undergoing pancreaticoduodenectomy.

Melanoma of unknown primary in the pancreas: should it be considered primary?

BACKGROUND: Malignant melanoma is characterized as highly malignant due to its rapid growth and early metastasis. Metastatic melanoma from occult primary is rare. Melanoma of unknown primary in pancreas are even rear. But it is a biologically ill-defined and clinically understudied concept. CASE PRESENTATION: In this report, a 43-year-old man was diagnosed with pancreatic carcinoma. Extended total pancreatectomy together with portal vein reconstruction and extensive lymphadenectomy were performed in our hospital. The patient was diagnosed with pancreatic malignant melanoma after pathological examination. He was still alive 20 months after the operation without any evidence of recurrence. CONCLUSION: The described case highlights the possibility of primary pancreatic malignant melanoma and the treatment strategies of this rare carcinoma.

Treatment options for sclerosing angiomatoid nodular transformation of spleen.

BACKGROUND: To summarise the clinical features of Sclerosing angiomatoid nodular transformation (SANT) of the spleen and to compare the efficacy of three different surgical treatments. METHODS: We performed a retrospective analysis of patients with SANT of spleen treated at our center from 2009 to 2018. We compared the efficacy and safety of three different types of surgical procedures. ANOVA and the chi-square test were used for statistical analysis. RESULTS: A total of 37 patients were included. Most (35/37; 94.6%) were asymptomatic. A number presented as obscure boundary lesions such that malignancy could not be excluded. Open splenectomy was performed for 12 patients, laparoscopic splenectomy for 12 patients and laparoscopic partial splenectomy for 13 patients. Operation time (P = 0.355), blood loss (P = 0.135), length of hospital stay after operation (P = 0.271) and postoperative complications (P = 0.502) were comparable between the three groups. Duration of drainage tube placement was significantly longer in laparoscopic partial splenectomy patients (P = 0.006). Peak platelet count after operation was significantly lower in laparoscopic partial splenectomy patients (P < 0.001). CONCLUSION: Laparoscopic partial splenectomy appears to be a technically feasible and therapeutically effective approach for SANT.

Meta-analysis of randomized clinical trials of adjuvant chemotherapy for resected biliary tract cancers.

BACKGROUND: This meta-analysis was performed by analyzing randomized controlled trials (RCTs) to assess the potential prognostic value of adjuvant chemotherapy (ACT) for patients with resected biliary tract cancers (BTCs). METHODS: PubMed, EMBASE, and the Cochrane Library were searched for relevant articles published. Only RCTs affected by tumors of gallbladder, intrahepatic, perihilar, and distal bile ducts were considered. Data were pooled using a random-effects model. The primary endpoint of the study was overall survival (OS). RESULTS: The study identified 1192 patients who met the inclusion and exclusion criteria. ACT had nearly reached a significant better OS (HR, 0.88; 95% CI, 0.77-1.01; P = 0.07) and achieved a significant better RFS (HR, 0.83; 95% CI, 0.69-0.99; P = 0.04). The effectiveness of ACT for OS was significantly modified by fluorouracil-based ACT (HR, 0.83; 95% CI, 0.70-0.99; P = 0.04), but not by gemcitabine-based ACT (HR, 0.91; 95% CI, 0.74-1.12; P = 0.36). The survival benefit was also not modified by primary disease site, resection margin status, and lymph node status. CONCLUSIONS: ACT is correlated with favorable relapse-free survival compared with non-ACT for resected BTCs patients. Fluorouracil-based ACT could be viewed as a standard practice for resected BTCs patients regardless of the primary cancer site, lymph node or margin status.

MiR-205 suppresses tumor growth, invasion, and epithelial-mesenchymal transition by targeting SEMA4C in hepatocellular carcinoma.

Growing evidence indicates that microRNAs are involved in tumorigenesis and progression of hepatocellular carcinoma (HCC). However, the functional mechanisms of miR-205 in HCC remain largely unknown. Here, we demonstrate that miR-205 expression was significantly down-regulated in HCC tissues and cell lines and was correlated with metastatic pathologic features and shorter disease-free and overall survival. Overexpression of miR-205 dramatically inhibited HCC cell proliferation, apoptosis, migration, invasion, epithelial-mesenchymal transition (EMT) in vitro, and tumor growth in vivo. We subsequently identified semaphorin 4C (SEMA4C) as a novel target of miR-205. Furthermore, high expression levels of SEMA4C were frequently found in HCC tissues and were associated with poor prognosis. Ectopic expression of SEMA4C restored the suppressive effect of overexpressed miR-205 on migration, invasion, and EMT. Taken together, our findings provide new insight into the critical role of miR-205 in regulating tumor growth, invasion, and EMT of HCC, suggesting miR-205 may serve as a promising therapeutic target and novel prognostic indicator for patients with HCC.-Lu, J., Lin, Y., Li, F., Ye, H., Zhou, R., Jin, Y., Li, B., Xiong, X., Cheng, N. MiR-205 suppresses tumor growth, invasion and epithelial-mesenchymal transition by targeting SEMA4C in hepatocellular carcinoma.

Prognostic significance of mucinous component in hilar cholangiocarcinoma after curative-intent resection.

BACKGROUND: The presence of mucinous component has been indicated to have a prognostic value in adenocarcinoma. However, little is known regarding the clinicopathological characteristics and prognosis of hilar cholangiocarcinoma (HC) with mucinous component (HCM). METHODS: Between January 1996 and December 2014, a total of 61 HCM patients who underwent curative-intent resection at West China Hospital were retrospectively reviewed. The clinicopathological characteristics and survival of these patients were compared with a large cohort of 217 surgically resected conventional HC patients during the same period. RESULTS: The clinicopathological characteristics of HCM were distinct from conventional HC, including higher CA19-9 levels, larger tumor sizes, less differentiation, and a high frequency of liver parenchyma invasion, portal vein invasion, and lymphovascular invasion. HCM patients showed significantly worse recurrence-free survival (13.4 vs 23.9 months; P = .011) and overall survival (18.2 vs 32.1 months; P = .019) compared with conventional HC patients. Multivariate analysis confirmed liver parenchyma invasion, N stage, surgical margin, and histological grade as independent prognostic factors influencing overall survival in HCM patients. CONCLUSION: HCM showed distinct clinicopathological features, more aggressive biological behaviors, and poor prognosis in comparison with conventional HC. Therefore, the mucinous component is an adverse prognostic factor for HC.

Abdominal drainage to prevent intra-peritoneal abscess after open appendectomy for complicated appendicitis.

BACKGROUND: Appendectomy, the surgical removal of the appendix, is performed primarily for acute appendicitis. Patients who undergo appendectomy for complicated appendicitis, defined as gangrenous or perforated appendicitis, are more likely to suffer from postoperative complications. The routine use of abdominal drainage to reduce postoperative complications after appendectomy for complicated appendicitis is controversial.This is an update of the review first published in 2015. OBJECTIVES: To assess the safety and efficacy of abdominal drainage to prevent intra-peritoneal abscess after open appendectomy for complicated appendicitis. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library, 2017, Issue 6), Ovid MEDLINE (1946 to 30 June 2017), Ovid Embase (1974 to 30 June 2017), Science Citation Index Expanded (1900 to 30 June 2017), World Health Organization International Clinical Trials Registry Platform (30 June 2017), ClinicalTrials.gov (30 June 2017) and Chinese Biomedical Literature Database (CBM) (1978 to 30 June 2017). SELECTION CRITERIA: We included all randomised controlled trials (RCTs) that compared abdominal drainage and no drainage in people undergoing emergency open appendectomy for complicated appendicitis. DATA COLLECTION AND ANALYSIS: Two review authors identified the trials for inclusion, collected the data, and assessed the risk of bias independently. We performed the meta-analyses using Review Manager 5. We calculated the risk ratio (RR) for dichotomous outcomes (or a Peto odds ratio for very rare outcomes), and the mean difference (MD) for continuous outcomes with 95% confidence intervals (CI). We used GRADE to rate the quality of evidence. MAIN RESULTS: We included six RCTs (521 participants), comparing abdominal drainage and no drainage in patients undergoing emergency open appendectomy for complicated appendicitis. The studies were conducted in North America, Asia and Africa. The majority of the participants had perforated appendicitis with local or general peritonitis. All participants received antibiotic regimens after open appendectomy. None of the trials was at low risk of bias.There was insufficient evidence to determine the effects of abdominal drainage and no drainage on intra-peritoneal abscess at 14 days (RR 1.23, 95% CI 0.47 to 3.21; 5 RCTs; 453 participants; very low-quality evidence) or for wound infection at 14 days (RR 2.01, 95% CI 0.88 to 4.56; 5 RCTs; 478 participants; very low-quality evidence). The increased risk of 30-day overall complication rate (morbidity) in the drainage group was rated as very low-quality evidence (RR 6.67, 95% CI 2.13 to 20.87; 1 RCT; 90 participants). There were seven deaths in the drainage group (N = 183) compared to one in the no drainage group (N = 180), equating to an increase in the risk of 30-day mortality from 0.6% to 2.7% (Peto odds ratio (OR) 4.88, 95% CI 1.18 to 20.09; 4 RCTs; 363 participants; moderate-quality evidence). There is 'very low-quality' evidence that drainage increases hospital stay compared to the no drainage group by 2.17 days (95% CI 1.76 to 2.58; 3 RCTs; 298 participants).Other outlined outcomes, hospital costs, pain, and quality of life, were not reported in any of the included studies. AUTHORS' CONCLUSIONS: The quality of the current evidence is very low. The effect of abdominal drainage on the prevention of intra-peritoneal abscess or wound infection after open appendectomy is uncertain for patients with complicated appendicitis. The increased rates for overall complication rate and hospital stay for the drainage group compared to no drainage group is also subject to great uncertainty. Thus, there is no evidence for any clinical improvement by using abdominal drainage in patients undergoing open appendectomy for complicated appendicitis. The increased risk of mortality with drainage comes from eight deaths observed in just under 400 people recruited to the studies. Larger studies are needed to determine the effects of drainage on morbidity and mortality outcomes more reliably.